Ku-band microminiature modulators were designed to convert a 10 mW signal at 400 MHz to a 10 mW signal at 15 GHz. The designs incorporate gallium arsenide Schottky barrier varactors used in upper-sideband up-converters. The use of Ku-band microstrip circulators and hairpin resonator bandpass filters at 2.1 GHz and 2.5 GHz is included. The design and fabrication of a single up-conversion unit with a double up-conversion unit are compared. Various filter configurations are studies, and the use of both alumina and quartz substrates are considered. The various impedance matching networks are evaluated using computer aided design techniques.